Method of making solid cast refractory articles



Jan. 29, 1929. 1,700,288

G.. s. FULcHER METHOD OF MAKING SOLID CAST REFRACTORY ARTICLES Filed oct. '18, 1927 /l/ /lll/l/l l ll l [Jl/lll /l/ll/ mensa Jan. 29, 1929.

UNITED STATES PATENT OFFICE.

GOBDONVS. FULGHEB, OF COBNIN G, NEW YOBK,ASSIGNOR T0 CORNING- GLASS WORKS, OF OORNING, NEW YORK, A CORPORATION 0F NEW YORK.

i `HI|!|'.I!IBOD OF MAKING SOLID CAST REFRACTOBY ARTICLES.

Application led October 18, 1927. Serial No. 226,986.

This invention `relates to im rovements in refractories, and more particu arly to the manufacture of solid cast refractory articles free from internal iaws or voids.

Cast refractory articles of the character to which this invention relates are produced by subjecting raw materials, such as ores consisting largely of lumina, s1l1ca, zirconla and the llke, to high temperatures, whereby they become fused and melted together, after which they are poured into molds of suitable shapes and sizes, and annealed. Due to the lgreat difference in volume between the liquid and solid 'states of these .materials, the shrinkage which takes place upon their solidiication creates voids or cavities in the finished product. These are commonly known in the art as pipe and are .objectionable as they increase the rapidity of deterioration of the article and consequently reduce its period of utility. Furthermore, such pipe lightens the casting and may make the specific gravity of the article less than that of the material in connec tion with whichit is used. This is particularly true when the refractory is used to line glass melting tanks as it may give the article a tendency to iioat away from its predetermined position in the liquid glass, especially if the tank is provided with exterior insulation. Thus the stability of the article and, under certain circumstances, its utility may be affected.

It is an object of the present invention to produce a cast refractory -article which will be free from such pipe and the consequent disadvantages above set forth.

A feature of the invention is the second pouring of the refractory material prior to the complete solidiication of the material of the first pouring, whereby the pipe formed in the material of the first pouring by the solidication of a portion thereof is filled, and the refractory material used in the second pouring unites with that of the first pouring to form a homogeneous mass.

The above and other objects are attained by practicing the method constituting the subect matter of the present invention,

`properly space the mol which will be fully set forth and claimed in the following specification, and illustrated in the accompanying drawing, in which:

Fig. 1 is a longitudinal, sectional view through a mold and casting illustrating the formation of the, ipe within the casting upon completion ofp the first pouring;

Fig. 2 is a similar view illustrating the mold prepared for the second pouring;

Fig. 3 is a similar view showing the mold upon completion of the second pourin and after the complete solidiiicatlon o the liquid forming the article; and

Fig. 4 is a perspective view, on a reduced scale, of a finished block made by the invention set forth herein.

Referring to the drawings, 10 designates a mold of any suitable substance and configuration but, for the purpose of illustrating my inventlon, it is shown as constructed to form a cast refractory block of the type used to line glass melting tanks or the like. The mold includes bottom, side and end walls 11, formed of sand bonded together by linseed oil and baked to produce slabs, which are connected in an suitable way, as by cementing them toget er alon adjacent edges to form a box. A top sla 12 is secured to theupper edges of the side and end walls 11, an is provided with ay central opening or gate 13- through which the refractory material is poured. 4

The mold is laced within a container 14, of metal or ot er suitable substance, and is supported in spaced relation tothe bottom of the container by suitable heat insulatin bricks 15. A slab 11 may be interposed between the bricks and the mold bottom but is not absolutely essential to the hereindescribed invention. Restin upon the top slab 12 of the'mold is a s ab 16, provided with a central opening 17 arranged to register with the openin 13 in slab 12. To 10 from the sides of container 14, and to prevent the slabs 11 from bulging during or after the pouring o eration, insulating bricks 18 are arrange in sfpaced relation to each other at the sides o the mold. The interstices bctween the bricks are filled with a suitable heat insulating material 19, such as silocel. Su ported on the slab 16 is a font-mold 20 w}luch, in the present instance, has a tapered cylindrical od of cast iron or the like. The reduced en of said font mold is disposed upwardly, so that it may be readily removed from the font after the pouring has taken place. The space between the font mold and the walls of the container 14 is filled with theinsulatin material 19 to completely insulate the mol and to prevent too rapid cooling of the cast- Vhen it is desired to cast an article the mold, prepared as above described, is placed in position to receive the molten refractory, which is then poured into the mold through the font mold 20. The molten refractory is poured to a hei ht about three inches above the lower en of the font mold, as shown in Fig. 1, and due to the shrinkage of the material, while solidifying, the font will become exhausted of molten material thus forming a pipe or void 21 within the casting.

Before the casting has completely solidilied, the insulatin material between the font mold 2O and t e container is removed, together with the font mold, and the font 22, formed by the setting of the molten material at the lower end of the font mold,

is broken away to expose the pipefas shown in Fig. 2. A new cover slab 12 is then placed on the casting and the font mold is re laced, whereupon a second pouring is e ected, as shown in Fig. 3,' so that the pipey becomes com letely filled and the castin is thus made so id. The second pouring ta es place within a reasonably short time after the first pouring, that is before the li uid of the first pouring has completely solidi ed, so that the material of the second pourin will unite with that of the first pouring, an form a homogeneous mass. In the second pourin the font mold 20 is nearly lled with the mo ten refractory material to insure a suiicient supply of the molten material to fill the pipe.

When the outside of the second font 23 has set, the font mold is removed and the font is surrounded with insulating material. After complete solidifiation of the cast article 24, the font 23 is broken away "and any scar 25 formed thereby is smoothed to remove objectionable projections. The casting is then covered with heat\in sulating material and set aside to anneal, as explained in detail in Patent 1,615,750, issued to me on January 25, 1927. After annealing the casting is removed and, if so desired, any or all of the surfaces thereof may be ground smooth and trued.

There are instances when a large scar,

' ,wooneesuch as 25, mayv reve objectionable and, smce the size of t el scar is ldetermined by the 'diameter of the gate, it may be vfound desirable to use a relatively small gate, and

thus necessitate the use of. a,plurality of fonts in succession to supply liquid until the casting has completely solidified.

Due to the rapidity of solidiication of the molten refractory material, and its tendency to produce a uniform external crust about the casting, upon contact with the cooler mold surfaces articles having a greater depth than the size ofthe gate opening cannot be poured free from pipe with a single pouring, as the material will solidify and close the gate, thus reventing the molten material in the font rom entering the mold as shrinkage of the contents thereof takes place. Thus the use of a plurality of fonts in succession, as just described, must be resorted to when the thickness ofthe casting exceeds the diameter of the largest ate which can be used in producing it. olid cast articles free from pipe canlbe roduced with a single pouring 1f the thic ess of the casting is less than the diameter of the permissible gate.

Thus it will be seen that, by practicing the method herein described, refractory articles of any thickness may be cast solid and free from voids and similar imperfections.

While in the foregoing there has been shown and described the preferred embodiment of this invention, it is to be understood that various modifications in the details of procedure, as well as in the apparatus used, ma be resorted to within the scope of the fo owing claims.

I claim:

1. The method of making solid cast refractory articles whichl` includes pourin molten refractory material into a mold, aE lowins a portion of said material to solidify and rink, and feeding additional molten refractor material into the moldl to comensate or the shrinkage of the material rst poured.

2. The method of making solid cast refractory articles which includes pourin molten refractory material into a mol forming a font of the refracto material to supply additional material to t e mold as the material therein solidifies and shrinks,

vbreaking` away the font, and pouring adsate for other shrinkage of the material, and the contents thereof solidify and shrink, annealing the article. breaking said font away after it has become 4. The method of making solid cast reexhausted of molten refractory material, and 10 fractory articles which includes pourin forming other fonts of the refractory ma- 5 molten refractory material into a mol terial to supply still further material to the forming a font of the refractory material to mold as its contents solidify and shrink. v supply additional material to the mold as GORDON S. FULCHER. 

